Core drill



CORE DRILL R. C. BAKER Filed Jan. 31, 1928 /7 INVENTORQ 3' I 4%.! LZ? ATTORNEYS.

April-29, 1930.

sgg 1| Patented Apr. 29,v 1930 UNITED sTATs'lsfPCATENr GFFIC REUBEN C. BAKER, 0F COALINGA, CALIFORNIA, ASSIGNOR TO BAK-:ER OIL TOOLS, INC.,

'I CORE A A CORPORATION OF CALIFORNIA DRILL Application met Janary 31, islas. serial No. 250,829.

This invention relates to' deep well drilling equipment and particularly pertains to a hollow rotary drill for drilling oil wells.

Hitherto, drill bits utilized in drilling wells by the rotary method were designed to act over the entire end area of the Ibore when sinking a well and advance the bore by pulve'rizing all of tlie formation encountered, This was necessary because the cuttings were removed by circulating a fluid downwardly through the drill pipe to the point of opera` tion, and thence, upwardly around the pipe to the surface. Therefore, the cuttings had to be suiiiciently'pulverized to vpermit them to be elevated by the fluid.

vance upwardly through the drill. lA Huidy is circulated downwardly through the drill to elevate the cuttings. The circulating fluid also has access to a certain extent to the core passing upwardly through the drill pipeso that finely divided particles thereof will be carried to the surface. By pulverizing but a portion of the end area of the bore when advancing through formation, the drilling effort will be minimized and consequently the drilling will be expedited.r Also, by causing the center portion of the formation being penetrated to pass upwardly in the drill pipe, samples of the formation being panetrated will be recovered for inspection wi-ien the drill pipe is removed from the well. This,

is advantageous as it permits analysis of the different formations encountered which is of a particular help to geologists in determinin the presence ,of oil.

4ne form which the. invention may assume is exemplified in the .following vdescription and illustrated by way of example in the accompanying drawings, in which Fig. is a view in side elevation of` adrill embodying the preferred form of my invention.

Fig 2 is a/central vertical section through the same showing it penetrating into formation. y

Fig. 3 is ar transverse section taken on line III-III of Fig. 2.

Fig. 4 is a transverse section taken on line IV-IV of Fig. 2. l

hollow drill head having athreaded upper Referring more particularly to theiaccompanying drawings, 10 indicates a cylindrical end 11- whereby it may be connected to a ldrill pipe. The lower end of the head is enlarged and is interiorly threaded as at 12 so that it maybe threadedly connected with` a drill I barrel 14. This drill barrel is tubular and at its lower end it is exteriorly threaded to receive a drilling shoevor -bit 15.

This arming bit is formed with atyiindrical body portion 16 interiorly threaded so that it may be threaded onto the lower end of the drill barrel 14. At its lower end the body portion 16 of the drilling bit is formed with a plurality of cutting teeth 17 arranged in a circle about the center o fathe bit. Such a drilling bit is described and claimedin a co-pending application entitled Drillingv shoe, filed April 27,1927, Ser. No. 186,908. It

will suflice to say that by arranging the teeth in a circle substantially equal in exterior diameter to the diameter of the bore, when sok revolved the shoe or bit will cut away a circular section at the perimeter of the bore, leaving a central Ycore or section of formatlon Arranged interlorly and concentric to the drill barrel'is a core tube 18. This core tube f extends the entire length ofthe drill barrel andis'relatively fixed thereto. As illustrated in the drawings, the exterior diameter of the core tube isl lessi than the interior `diameter of the drill barrel so that an annular passageway will be' formed between the drill barrel and the l core tube to permit circulating fiuid, pumped downwardly through the head 10 to be discharged (downwardly between the drill:

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barrel and core tube to both lubricate the cutting teeth 17 and to wash away the cuttings.

Asbefore stated the drill barrel and core tube are relatively fixed together. This I accomplish by cutting aligned slots 19 in the drill barrel and core tube at spaced intervals. I enclose each slot with 'a sleeve 20 which is welded to the drill barrel and core tube, so as to firmly fix the two elements together and to prevent communication between theannular space between the drill barrel and core tube and the exterior of the drill barrel. The slots, however, serve as circulation or wash openings between the interior of the core tube and the space surrounding the exterior of the drill barrel. The slots as illustrated are arranged on diametrically opposed sides of the device and relatively staggered.

At its upper end the coretube is plugged as shown in Fig. 2, while. at its lower end it aligns with and abuts against a split core trap ring 21. This trap ring 2l formed with a tapered exterior surface 22, which nests with'- in tapered ribs 23 within the body of the drill-` in bit 16.

n operation of the device, it is constructed and assembled as shown in the drawings and run in the hole at the end of a drill pipe suitably connected to the drill head 10. It is then revolved and a circulating fluid is pumped downwardly through the drill pipe. This circulating fluid will pass through the annu- Y lar space between the drill barrel and core tube and will discharge between the ribs 23 in the drilling shoe and will lubricate the cutting teeth 17 and carry .-away the' cuttings. After passing out of the drilling shoe, the circulating fluid will pass upwardly around the exteriorof the drill barrel and seek the surface. As the drilling bit penetrates the forma-,

` barrel will have access to the material tion,.it will cut away an annular space at the perimeter of the bore, leaving a central portion of a diameter substantially the same as the interior diameter of the core tube 18. This unpulverized portion of the formation penetrated will pass upwardly through the split trap ring 2l and into the core tube 18 as Ehe drilling bit advances through the formalon.

`As the wash or circulating slots 19 extend between the interior of the core tube and the exterior ofthe drill barrel, vthe circulating Huid discharging upwardly around the drill passing upwardly into the core tube. Thecirculating fluid will actfto disintegrate a greater part of the soften formations by coming in contact with thel core through the wash slots 19. These softer formations and any finely divided substances will lbe carried to the surface b y the circulating fluid and the Idrill can conf tinue to advance through the formation until the drill bit becomes dull or the core tube becomes Filled with the harder parts of the formation that will notbe disintegrated by the circulating fluid.

It is obvious that by merely pulverizing but a portion of the end area o f the bore, the drilling effort will be minimized and consequently the drilling will be expedited. Also, the circulating iiuid is delivered. directly to the point of operation, fully lubricating the cutting teeth and rapidly carrying away the cuttings. 4

As the interior surface of the split trap ring 21 is serrated, the core entrapped within the core tube may be elevated to the surface when the drill4 `is removed from the hole. This trap ring 2l pinches off the core and acts to retain it within the core tube. After the drill has been brought to the surface, the samples of formation contained within the core tube may be removed for examination. This bringing ofsamples to the surface is important as it aids geologists in determining whether or not the formations being penetrated are favorable to the presence of oil.

While I have shown the preferred form of my invention, it is to be understood that various changes may be made in its construction by those skilled in the art without departing from the spirit of the invention, as defined in theappen ded claims.

Having thus described my invention, what longitudinally disposed chamber formed'l therein, said chamber lacing open at its lower end, a bit at the lower end of said body adapted to cut away an annular area at the l perimeter ofthe bore leaving a portion of formation in alignment with the chamber of an area permitting it to enter the chamber as the drill is advanced through formation, means permitting circulating fluid to be discharged downwardly through the body without gaining access to said chamber, said body having a plurality of comparatively large openings formed therethrough at spaced intervals along its lengthy exposin formation `in the chamber to circulating uid passing along the body exteriorly of the body.

2. A well drill including a bodyhavingv a longitudinally disposed chamber formed therein, said chamber having a closed upper end and an open lower end, a bit at the lower end ofthe body adapted to cut away an annular area at the perimeter of the bore leaving a portion of formation in alignment ywith the chamber and of an area permitting it to enter the chamber as'the drill is adj vanced through formation, saidbody having, l

' the'interiorof the chamber and the exterior A ,the exterior of" the body.y t

barrel to ga 3. A vwell drill comprising a hollow drill barrel, a drilling bit fixed to the lower end of v the drill barrel and adapted to cut awa an annular area at the perimeter of the ore leaving a portion of formation at the center of the bore, a core tube xed within the drill vbarrel l* and of a diameter less than the in' terior diameter of the drill barrel, the upper end of said core tube being closed, the lower end of said` core tube being open and extending to a point adjacent the bit whereby it may be passed over the formation remaining at the center ofthe bore as the drill advances, a plurality of enclosed passageways spaced at intervals along the drill forming communication between the interior ofthe'core tube and the/exterior of the drill barrel to permit circulating fluid passing exteriorly of the balrrel to gain access'to the formation in the tu e. t

4. A well drill comprising au h'ollow head, a ^drill barrel threadedly connected at its upper end to said head, a drilling bit, said bit having a hollow -cylindrical bodyportion threadedly connected to the lower end of the barrel, cutting teeth on the lower end of the bitadapted to cut away an annular area at the perimeter of the bore leaving a portion of formation at the center of the bore, a core tube of a diameter less than the interior diameter of the drill barrel, said core tubefbeing vfixed concentrically within the drill barrel.

with its lower end substantially in alignment with the lower endl of the drill barrel whereby itl may pass over the vformation at the, center of the boreV as the drill is advanced,v thel space occurring between the barrel and the tube permitting circulating fluid to pass between theb'arrel and the `4 tube to the bit,' a plurality of enclosed passageways extend ing between the 'core tube' and the dillbarrel at intervals intermediate the ends thereof forming communication 'between lthe interior ofthe core tube and the exterior ofthe barrel to permit 'circulating Huid. exteriorly of the access to the linterior of the core;tube, sai passageways not communicating with the space between the tubeand `the barre..

5.v A'well drill comprising a hollow head, a drill barrel threa'dedly connected at its upper end to said head, a drilling bit, said bit havin a hollow cylindrical body portion threa edlyconnected to the lower end of the barrel, ,cutting teeth on the lower end ofthe bit adapted to cut away an annular area at with its lower end substantially inalignment with the lower end of the drill barrel where'- by it may pass over the formation at the center'of the bore as .the drill is advanced, the .space occurring between" the barrel and the tube permitting circulating fluid' to pass between the barrel andthe tube to the bit, a plurality of enclosed passage ays extending between the core tube and the drill barrelrat intervals intermediate the .ends thereof forming communication between the interior of the core tube and the exterior of the barrel to permit circulating luidexteriorlyofthe barrel to `gain access to the .interior of the tances apart', a 4 trap jring having a tapered exterior surface nesting within said ribs ina lposition to align with and abut against the lower end of said core tube.

REUBEN C. BAKER.

the perimeter o f the bore leaving a portion of formation at the centerof the bore, a core v tube of a diameter less than the interior di.

ameter of the drill barreli said core tube being fixed concentrically wi the barrel 

